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A guide to the selec in accordance with “Fire detection and fire alarm Pic courtesy of Cavicel Srl
Part 1: Code of practice for system design, installation, commissioning and maintenance
By Marcelo Celantano of Cavicel Srl
THE NEW STANDARD BS 5839-1:2002 supersedes the previous 1988 edition, which has been withdrawn on 15 July 2003. Projects designed to BS 5839-1:1988 may, by agreement between contractual parties, be completed to that edition. MAIN CHANGES ●
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Two different levels of resistance of cables to damage during the course of a fire are recognized, and recommendations for application of each type are provided. The use of fire resisting cables is now recommended for all manual call points and automatic fire detector circuits. The use of fire resisting cable is also recommended for all mains power supply circuits. Recommendations for networked systems, particularly in respect of cable types, are included. New guidance of segregation. New guidance on cable fixing and installation. Restriction on use of multicore cables.
USE OF FIRE RESISTANT CABLES This standard makes recommendations for two levels of fire resistance of cable
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INTERNATIONAL FIRE PROTECTION www.ifpmag.com
systems, termed “standard” and “enhanced”, according to the type of building and fire alarm system installed: ●
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the use of cables with “standard” fire resistance is recommended for general use; the use of cables with “enhanced” fire resistance is recommended for systems, in particular building types, in which cables might need to operate correctly during a fire for periods in excess of those normally required for single phase evacuation of a building. Examples are unsprinklered high rise buildings with phased evacuation arrangements and premises of such a nature or size that areas remote from the fire could continue to be occupied for a prolonged duration during a fire that might then damage cables serving parts of the fire alarm system in occupied areas.
The distinction between two levels of performance is, therefore, made in this standard to enable designers and specifiers to specify “enhanced” performance cables in situations in which it is considered that a higher level of fire resistance is desired. TYPES OF FIRE RESISTANT CABLES The Code specifically recommends only three types of cables: ●
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mineral insulated copper sheathed cables conforming to BS EN 60702-1: 2002, IEC 60702-1: 2002 – Mineral insulated cables and their terminations with a rated voltage not exceeding 750 V; cables conforming to BS7629-1/2: 1997 – Specification for 300/500 V fire resistant electric cables having low emission of smoke and corrosive gases when affected by fire; armoured fire-resistant cables conforming to BS 7846: 2000 – Electric cables. 600/1000 V armoured fire-resistant cables having thermosetting insulation and low emission of smoke and corrosive gases when affected by fire.
However, the Code also accepts the use of cables rated at, at least, 300/500V that provide the same degree of safety to that afforded by compli-